The invention relates to a method of controlling the adjustable operating parameters of an internal combustion engine with direct fuel injection which includes a cylinder with a piston forming a combustion chamber.
Air and fuel supplied to the combustion chamber of an internal combustion engine forms therein a fuel/air mixture, which is ignited by a spark formed between the electrodes of a spark plug. Under partial load, the mixture forms a stratified charge over a large engine operating range. The stratified charge is achieved by injection of the fuel during a relatively late phase of the compression stroke. In order to improve fuel consumption, and consequently, the efficiency of the engine, an internal mixture with high lambda values is desired wherein, depending on the engine load, a rich and consequently easily ignitable mixture is formed at the electrodes of the spark plug, but in the rest of the combustion chamber, the mixture becomes leaner with increasing distance from the electrodes of the spark plug.
Such an internal combustion engine is known, for example, from DE OS 43 24 642 A1.
The comparatively low NO.sub.x -- and CO emissions and the large amount of excess air present during stratified charge operation may lead to a deterioration of the operating behavior of the internal combustion engine by ignition misses and a slow combustion. A good operating behavior, that is smooth engine operation, is therefore usually achieved by substantial throttling of the intake air. This however leads to throttling losses of the engine performance. Known methods for the control of the adjustable operating parameters require extensive changes in the engine design in order to facilitate the continuous gathering of measurement data which give an indication of the operating state of the internal combustion engine on which an optimal adjustment of the engine operating conditions could be based.
It is therefore the object of the present invention to provide a method of controlling the adjustable operating parameters of an internal combustion engine with direct fuel injection, wherein without changes in the engine design, at every operating point individual measuring data with information concerning the respective engine operating condition can be determined on which data the operating state-dependent adjustment of the engine operating conditions can be based.